how to build nested where on zend db

Hello everyone i want to build this query on zend db (zf1.9)

SELECT `p`.*, `r`.`name` AS `retailer`, `placer`.`name` AS `placer_name`, `placer`.`contact_firstname` AS `placer_firstname`, `placer`.`contact_lastname` AS `placer_lastname`, `placer`.`role_id` AS `placer_role_id`, `editor`.`name` AS `editor_name`, `editor`.`contact_firstname` AS `editor_firstname`, `editor`.`contact_lastname` AS `editor_lastname`, `editor`.`role_id` AS `editor_role_id` FROM `pos` AS `p`
LEFT JOIN `retailers` AS `r` ON r.id = p.retailer_id
LEFT JOIN `members` AS `placer` ON placer.id = p.placer_id
LEFT JOIN `members` AS `editor` ON editor.id = p.editor_id WHERE (p.designer_id=116) AND ((placer.name LIKE '%demo%') OR (placer.contact_firstname LIKE '%demo%') OR (placer.contact_lastname LIKE '%demo%') OR (r.name LIKE '%demo%')) AND (`r`.`name` LIKE '%M%') ORDER BY `p`.`id` asc

how can i do that?my problem is only

WHERE (p.designer_id=116) AND ((placer.name LIKE '%demo%') OR (placer.contact_firstname LIKE '%demo%') OR (placer.contact_lastname LIKE '%demo%') OR (r.name LIKE '%demo%')) AND (`r`.`name` LIKE '%M%')

((placer.name LIKE '%demo%') OR (placer.contact_firstname LIKE '%demo%') OR (placer.contact_lastname LIKE '%demo%') OR (r.name LIKE '%demo%'))

third:

(`r`.`name` LIKE '%M%')

In ZEND every AND is an seperate where-clause and might look like something like this (untested! only for better understanding!):

->where("p.designer_id=116");
->where("(placer.name LIKE ?)
OR (placer.contact_firstname LIKE ?)
OR (placer.contact_lastname LIKE ?)
OR (r.name LIKE ?)", '%demo%', '%demo%', '%demo%', '%demo%');
->where("r.name LIKE ?", '%M%');